基于NOAA16-AVHRR数据反演中纬度陆地上空云类型及云顶高度信息

Cloud Type Classification and Height Retrieval by NOAA16-AVHRR Data in the Mid-latitude Terrestrial Area

以NOAA16-AVHRR数据为数据源,使用分裂窗技术反演得到云类型信息。根据11μm通道亮温图与分裂窗通道(11μm和12μm通道)之间的亮温差值图构建二维直方图。通过选择合适的直方图阈值,保证了所反演的中纬度陆地上空云类型信息的有效性。根据大气垂直温度数据,分析11μm通道亮温图,获得中纬度陆地上空云顶高度信息。通过相隔大约10 km的两台便携式全自动激光雷达(PAL)系统获得同步云信息数据。将卫星反演结果与PAL的双点观测结果进行比较,其结果显示出很好的一致性。

Cloud information was retrieved from NOAA16-AVHRR data using the split-window technique. Two-dimensional histograms were constructed on the basis of the brightness temperature of the 11 μm channel and the brightness temperature difference between the splitwindow channels （11 μm and 12 μm channels）. Appropriate thresholds in the histogram enable the cloud-type classification in the mid-latitude terrestrial area. According to the vertical temperature profile of atmosphere, cloud height was retrieved by analyzing the brightness temperature of the 11 μm channel in the mid-latitude terrestrial area. Synchronous cloud data were obtained by two portable automated lidar （PAL） systems that were located approximately 10 km from eachother. The comparison between the satellite and PAL systems show well consistency of the two independent methods.